librfm95

About

Static avr-libc library providing basic support for RFM95 radio modules. Other RFM9x radios might work as well, but were not tested yet.

I'm impressed how well these radio modules work; the range achieved with simple wire antennas as well as the reliable packet transmission.

This is work in progress. Currently available is (FSK and LoRa):

• Transmit a packet
• Blocking receive a single packet with timeout
• Async'ly receive a packet (MCU sleeps or does something else until reception)

Usage

1. Include librfm.h and librfm.a in the project
2. Implement the _rfm* functions in librfm.h in the application (this is to make the library device and CPU frequency independent)
3. Route interrupts occurring on DIO0 and DIO4(FSK)/DIO1(LoRa) to rfmIrq()

Range

FSK

Transmitting with +17 dBm, reception stopped with an RSSI of about -125 dBm at almost 2.7 km distance - with simple wire antennas, and a low hill in between.

Compared to the RFM69 at +13 dBm, it does make it a few hundred meters further - seems fair enough!

LoRa

TODO 🙂